1. Field of the Invention
This invention generally relates to a semiconductor device and a fabrication method of the same, and in particular, relates to a semiconductor device having a silicon nitride layer on a semiconductor layer and a fabrication method of the same.
2. Description of the Related Art
A semiconductor luminescent device such as a semiconductor laser emitting a light or a light-emitting diode (LED), or a semiconductor optical receiver such as a photo diode receiving a light is used in a field of an optical communication or an optical memory media. Japanese Patent Application Publication No. 2005-317572 discloses a semiconductor laser as an optical semiconductor device that has a ridge-type stripe structure.
In the semiconductor laser, an active layer emitting a laser light is, for example, between an n-type semiconductor layer and a p-type semiconductor layer. When a current is applied between the n-type semiconductor layer and the p-type semiconductor layer, a laser light is emitted. In the photo diode, a light is detected when a current flowing between an n-type semiconductor layer and a p-type semiconductor layer is detected, the current being caused by a carrier being excited by a light received at an receiving layer between the n-type semiconductor layer and the p-type semiconductor layer.
In the semiconductor device, there is a demand for reducing a resistance of a conductive layer such as a contact resistance between the n-type or the p-type semiconductor layer as a conductive layer in the compound semiconductor layer and the electrode. And there is a demand for limiting a leak current in an interface between the compound semiconductor layer and an insulating layer.